The US government plans to launch "a three and a half year initiative
to develop an urban drone detection system." The Aerial Dragnet
program is to use off-the-shelf commercial components and mostly
established technologies and methods to create a network of floating
or tethered platforms that will ultimately provide 95% efficient drone
identification in urban areas up to 180 square kilometers. The call to
proposers states that the total cost of the system for a city should
be around $90,000, and would likely include the ability to identify
the micro-Doppler signatures given off by UAVs -- and birds.
Unmanned aerial systems are becoming platforms "for hostile
reconnaissance, targeting, and weapon delivery," warns the government
document, noting drones are hard to detect because they're small and
fly slowly at low altitudes. "In future urban battlegrounds, U.S.
forces will be placed at risk by small UAVs which use buildings and
naturally-occurring motion of the clutter to make surveillance